How to Remove Hard-Water Scale from a Glass Shower Screen

By Priya — deep-clean specialist, Sydney inner-west.

Vinegar doesn’t work on hard scale. I’ll say it again because every cleaning blog repeats the vinegar myth like it’s gospel: vinegar is a mild acid that handles soft, fresh limescale. Once the scale has been baking on a frameless shower screen for two summers, vinegar bounces off it and you wear out your shoulder scrubbing.

What works is oxalic acid. The Aussie consumer name for it is Bar Keepers Friend. Yellow tin, comes as a powder, sold at Coles, Woolies and Bunnings. Mix it with water, apply, wait 4 minutes, rinse — and 5-year-old scale lifts off glass like it was never there. I’ve cleaned screens that had been written off as “permanently fogged” with this method and the homeowner thought I’d swapped the glass.

The Aussie gotcha — and the thing that catches everyone — is that on Adelaide and Perth water (some of the hardest in the country), if you don’t squeegee the screen after every shower, the scale eventually etches the glass. Once it’s etched, no acid in the world will fix it. The “cloudy” look isn’t scale anymore, it’s pitted glass. Permanent. So this method works on scale up to about 2 years of buildup. After that, it’s a 70% recovery — better than nothing, not perfect.

What you’ll need

• Bar Keepers Friend — yellow tin, powder formula (NOT the liquid spray — the powder is more concentrated and works better here) — about $7 at Coles or Bunnings
• A non-scratch sponge (the white side of a Scotch-Brite Greener Clean, or a melamine sponge / “magic eraser”)
• Microfibre cloths — at least three
• Squeegee — Bunnings sells a $9 Sabco one that’s perfect
• Rubber gloves (oxalic acid will dry your skin badly without them)
• Eye protection
• Spray bottle of water for rinsing in-shower
• White vinegar (for the final neutralising rinse)
• Toothbrush for the silicone seal at the bottom

Step 1: Open a window and put on gloves

Bar Keepers Friend smells like nothing but it’s a real acid. Gloves on. If your bathroom is windowless, run the exhaust fan and prop the door open. Don’t mix it with bleach — every bottle of bathroom cleaner you have, leave outside the bathroom while you work.

Step 2: Wet the glass with warm water

Quick rinse with the showerhead. Warm, not hot. The water film helps the powder spread evenly and stops it sitting in dry powder spots that go gritty.

Step 3: Sprinkle Bar Keepers Friend onto a damp sponge

Don’t sprinkle it directly on the glass — it’ll fall off in clumps and waste product. A teaspoon onto the damp non-scratch sponge, work it into a paste with a couple of drops of water from the spray bottle.

Step 4: Apply in even strokes across the whole panel

Top to bottom, in straight horizontal strokes. You’ll feel the gritty paste glide over the glass. Don’t scrub aggressively — light, even pressure. The acid is doing the work, the slight abrasive in BKF (oxalate) is helping but it’s not the main attraction.

Cover the entire panel before going back to scrub anywhere harder. Let the paste sit on the glass for 4 minutes — set a timer.

Step 5: Tackle the heavy zones

Bottom 200 mm of the screen and around the door hinge area always have the worst scale (most water exposure). Re-apply BKF to the sponge and work these sections again. Light circular motion with the non-scratch side. You’ll feel the scale break down — the surface goes from gritty to smooth under the sponge.

Step 6: Rinse thoroughly with warm water

Showerhead, top to bottom, every panel. The water should run clear with no chalky residue. If you can still see white streaks, those are remaining scale areas — re-apply BKF and repeat.

Step 7: Vinegar rinse to neutralise

Spray the glass with white vinegar diluted 1:1 with water. This neutralises any acid residue (oxalic acid won’t damage the glass but it can dull chrome fittings if it sits) and lifts any final mineral haze. Rinse again with water.

Step 8: Squeegee the entire screen dry

Top-to-bottom in overlapping vertical strokes. Wipe the squeegee blade between strokes. The aim is zero water droplets left to dry. If you let droplets air-dry, you immediately deposit fresh scale — undoing what you just did. This is the ongoing maintenance habit too: squeegee after every shower and the screen never builds scale again.

Step 9: Toothbrush the silicone bead

The silicone seal where the glass meets the tile or the floor accumulates pink mould (Serratia marcescens) and black mould. BKF can damage silicone if left to sit, so don’t apply it there. Instead, a damp toothbrush with a drop of dishwashing liquid + a tiny pinch of bicarb scrubs the silicone clean. If the silicone is genuinely mouldy through (black inside, not just on the surface), the silicone needs to be cut out and replaced — see our re-silicone tutorial.

Step 10: Final dry buff with microfibre

One pass with a clean dry microfibre to catch any drips and finish the glass to a streak-free shine. Step back. The screen should look factory-fresh — every reflection sharp, no haze, no spots.

The daily prevention routine

30 seconds with a squeegee at the end of every shower, every shower, no exceptions. Hang the squeegee inside the shower (Bunnings sells suction-cup hooks for $4) so it’s never an excuse-to-skip moment. One vertical pull from top to bottom on each panel, finishing with a horizontal pull along the bottom edge to push water into the channel.

That’s it. No spray, no wipe-down, no products. Just shed the water before it dries. Households that adopt this from day one of a new screen never need the BKF method at all — and even in Adelaide and Perth, the screen looks brand new five years later.

The etching test — has the glass already gone?

After your BKF clean, run a fingertip across the glass under raking light from the side. Smooth = the glass is fine; etching has not occurred. Slightly grainy or pitted to the touch = the surface has etched and no further cleaning will fix it. At that point your options are:

• Glass restoration kits (Cerium oxide polish): A proper cerium oxide polish ($30, Repco automotive section) on a felt buffing wheel attached to a drill can polish out shallow etching. Slow work, 30-60 minutes per panel, but it does work for light etching.
• Glass replacement: A frameless 10 mm tempered shower panel is $300-500 supplied and installed by a glazier. Usually the right call for badly etched panels.
• Acid etch protection coatings: EnduroShield, Aquashield, ShieldGuard — these are nano-coatings applied to NEW or freshly polished glass that prevent further scale bonding. About $120 DIY kit, lasts 5-10 years. Worth doing on any new shower screen.

Why this matters in Adelaide and Perth specifically

Adelaide water comes substantially from the Murray and is hard — calcium and magnesium carbonate dissolved in solution. Perth water comes mostly from groundwater and dam catchments, also hard. Sydney water is much softer (it’s mostly Warragamba dam, low mineral). Melbourne water is among the softest in any major city. Brisbane is mid-range.

So a shower screen in Sydney can go years with only mild scale. The same screen in Adelaide will scale heavily in 6 months without daily squeegeeing. If you’ve moved cities, your old shower-cleaning routine may not work in your new city — calibrate the prevention to the local water hardness.

Chrome and stainless fittings nearby

Bar Keepers Friend on chrome is fine for short contact then rinse — it’ll lift water spots and soap scum. On chrome that’s been dwelling for over a minute, the oxalic acid can dull the polish. Apply quickly, rinse quickly, buff dry. For brass or unlacquered metals, skip BKF entirely — vinegar with a dab of toothpaste is the gentler route.

The Priya rule

Bar Keepers Friend (oxalic acid) for the scale, vinegar to neutralise after, squeegee after every shower forever. Adelaide and Perth water is hard enough that prevention has to be daily — every shower, 30 seconds with the squeegee. If you do that from day one of a new screen, you’ll never see scale build up at all. If you skip it for 18 months in those cities, expect permanent etching that no acid will reverse, and budget for a polish kit or replacement glass.

Got a screen with marks that didn’t shift even after BKF, or unusual chrome/brass tarnish next to the glass? Send us a write-up.